This invention relates to a medical hollow needle suitable to use as a medical hollow needle, such as a needle for hypodermic injection, dialysis, intravenous drip and blood-collecting, and a cannular needle, that is, the needle having a flow path in which a fluid, such as a liquid injection medicine and a blood, flows, and a method of producing thereof.
In a conventional method, the medical hollow needle, such as the needle for hypodermic injection, and a cannular needle has been produced by grinding a cylindrical member having a thin diameter. That is, the top end portion of the cylindrical member is grinded in an oblique direction with respect to the direction of the central axis of the cylindrical member so as to form an open bevel end face open in an oblique direction with respect to the direction of the central axis of the cylindrical member, in this way the medical hollow needle has been produced.
It is known that the thinner the wall thickness of a top edge portion of the cylindrical member is made, that is, the thinner the sharp edge portion of a medical hollow needle is made, the less blood vessel at the injection part of a patient or the like is hurt, and the less pain the patient feels at the injection part, at the time of injection or the like. In a conventional medical hollow needle, in order to extremely make a sharp edge portion thin, when an open bevel end face is grinded and formed, there is such an idea that grinding is performed in such a manner that the inclined angle of the open bevel end face to the center axis direction of the cylindrical member is extremely made small. However, in order to grind extremely making the inclined angle of the open bevel end face small, the area for forming the open bevel end face in the center axis direction of the medical hollow needle, that is, the area for grinding the cylindrical member becomes to be wider. As the result, the strength of the medical hollow needle is decreased since the cylindrical member becomes to be wide for its broad area. That is, it was difficult to extremely make the sharp edge portion thin without decreasing the strength of the medical hollow needle.
An object of the present invention is to provide a medical hollow needle and a method of producing thereof capable of extremely making a sharp edge portion thin without marring the strength of a medical hollow needle, taking the above-mentioned circumstances into consideration.